Playtest: Gamma Zo Verve 17
By Greg Raven
Gamma Zo Verve is a unique co-extrusion polyester string that combines two types of material. At the core is a softer, more elastic, and resilient red polyester. Embedded around the periphery of the red core are three sections (on 120-degree centers) of a stiffer black material that has a higher molecular weight. The black sections stand out slightly from the red core, giving Zo Verve an innate texture in the form of longitudinal ridges.
Gamma tells us this blend of materials allows for a more forgiving feel yet provides massive amounts of spin. Gamma tells us that Zo Verve is designed for players looking for maximum topspin, and polyester users of all levels.
Zo Verve is available in 16 (1.32 mm) and 17 gauge (1.25 mm) in black/red. It is priced from $17.45 for sets of 40 feet, $157.05 for reels of 360 feet. For more information or to order, contact Gamma at 800-333-0337, or visit gammasports.com. Be sure to read the conclusion for more information about getting a free set to try for yourself.
In the lab
We tested the 17-gauge Zo Verve. The coil measured 40 feet. The diameter measured 1.24-1.27 mm prior to stringing, and 1.20-1.22 mm after stringing. We recorded a stringbed stiffness of 73 RDC units immediately after stringing at 60 pounds in a Wilson Pro Staff 6.1 95 (16 x 18 pattern) on a constant-pull machine.
After 24 hours (no playing), stringbed stiffness measured 67 RDC units, representing an 8 percent tension loss. Our control string, Prince Synthetic Gut Original Gold 16, measured 78 RDC units immediately after stringing and 71 RDC units after 24 hours, representing a 9 percent tension loss. In lab testing, Prince Synthetic Gut Original has a stiffness of 217 and a tension loss of 11.67 pounds, while Gamma Zo Verve 17 has a stiffness of 236 and a tension loss of 16.92 pounds. Zo Verve added 16 grams to the weight of our unstrung frame.
The string was tested for five weeks by 43 USRSA playtesters, with NTRP ratings from 3.5 to 6.0. These are blind tests, with playtesters receiving unmarked strings in unmarked packages. Average number of hours playtested was 29. Gamma recommends 5-10 percent reduction in reference tension compared to a typical nylon reference tension. We passed this recommendation along to our playtest team.
Gamma Zo Verve feels thicker out of the package than the gauge would indicate, which may be a result of the three black ridge inserts. However, installing Gamma Zo Verve is little different from installing other polyester strings, which is a pleasant surprise because textured strings sometimes can present problems for the stringing technician.
No playtester broke his sample during stringing, 19 reported problems with coil memory, 10 reported problems tying knots, and one reported friction burn.
On the court
Our playtest team found a lot to like in Gamma Zo Verve, giving it five top-twenty ratings out of nine categories. These included fifth place overall of the 156 strings we’ve playtested to date both in the Control and Spin Potential categories, 11th overall in Durability, 18th overall in Resistance to Movement, and 20th overall in the Power category. Additionally, Zo Verve garnered ratings well above average in two categories: Playability and Tension Retention.
Three players broke the sample during play: Two at 6 hours and one at 9 hours. One of the playtesters who broke the sample at 6 hours rating the durability as “excellent.”
It’s easy to extrude a textured poly when the entire string is composed of the same material, but the trade-off is that any material strong enough to retain its edges as manufactured has that same material throughout the entire string. In Zo Verve, Gamma has gone to the extra effort of co-extruding a harder material for the edges, in such a way that it doesn’t compromise the basic playability of the string.
“This is a great string for players who use heavy topspin. It has the perfect combination of bite and power.” 4.5 male all court player using Wilson K Six One (16x18) strung at 60 pounds LO (Tecnifibre Red Code 17)
“This is a crisp, low powered string with great feel and excellent tension maintenance. The shaped construction grabs the ball and produces spin with minimal effort.” 4.0 male all court player using Wilson BLX Pro Open strung at 45 pounds CP (Tourna Big Hitter Blue 17)
“Excellent control and durability. Plays better after a few hours.” 4.5 male all court player using Wilson BLX Blade strung at 57 pounds LO (Wilson Hyperlast Spin 19)
“This is the perfect poly. Not only does it possess the expected durability, spin, and control, but it has comfort, touch, and feel.” 5.0 male serve-and-volley player using Volkl C10 Pro OS strung at 45 pounds LO (Gamma Zo Tour 16)
“This string has a more dampened feel than natural gut. The spin is excellent.” 3.5 male all court player using Wilson K Six One Tour strung at 50 pounds LO (Babolat VS Team 17)
“As a senior player with a continental grip, I typically do not prefer an all-poly set up. This string is the exception. Achieving results is a cinch. Spin and control are exceptional. After 15 hours, there is no noticeable loss of tension or control.” 4.0 male all court player using Pacific Raptor strung at 53 pounds LO (Pacific X Force/Gosen OG Sheep Micro 18/17)
“Excellent feel and touch at net. One of the most comfortable polys I’ve ever tested.” 5.0 male all court player using Wilson BLX Pro Open strung at 55 pounds LO (Wilson NXT 17)
“This is a very crisp string with amazing spin and control.” 5.0 male baseliner with heavy spin using Head Youtek Prestige MP strung at 55 pounds CP (Luxilon Alu Power 16L)
“This string snaps back powerfully. It has great feel with zero shock on off center hits. The spin is pronounced.” 5.0 male all court player using Dunlop Biomimetic 600 Lite strung at 54 pounds LO (Wilson NXT 17)
“Wow! This is a very playable poly. Spin and control are excellent. Groundies have power and volleys feel crisp. It even has nice feel on drop shots. Best of all, my arm loves it!” 4.0 male all court player using Prince O3 Red MP strung at 54 pounds CP (Gamma TNT2 Pro Plus 17L)
“This string is a spin monster. It has power and control. Some adjustment is required in the beginning, but the payoff is worth the wait.” 4.5 male baseliner with heavy spin using Head MicroGEL Prestige Pro MP strung at 55 pounds CP (Head Sonic Pro 17)
“This poly has all the advantages of a hybrid in a single string!” 4.0 male all court player using Head TXP strung at 57 pounds LO (Gamma Professional 18)
“Performs with remarkable control at a low tension. No trampoline here.” 3.5 male all court player using Pro Kennex Acclaim strung at 40 pounds CP (Head FXP/Babolat VS Team 17/17)
“This is an arm friendly poly with incredible power and durability. Touch is surprisingly good.” 4.5 male all court player using Head Liquidmetal Radical OS strung at 55 pounds LO (Luxilon Alu Power Rough 16L)
“After a short break-in period, playability shines.” 5.0 male all court player using Babolat Pure Storm Tour GT strung at 58 pounds CP (Prince Poly Spin 3D/Prince Synthetic Gut Original 16L/16)
“This string has a nice mix of power, control, and durability. Great feel from the baseline, and easy on the arm.” 5.0 male all court player using Babolat Pure Drive Roddick GT strung at 52 pounds CP (Babolat Pro Hurricane Tour/Babolat VS Team 16/17)
“This is a high quality durability string. The thin gauge increases spin.” 4.0 male all court player using Wilson nTour strung at 53 pounds LO (Solinco Tour Bite 18)
“This string has an impressive, if unlikely combination of comfort and durability.” 3.5 male baseliner with moderate spin using Prince O3 Blue strung at 60 pounds CP (Luxilon Alu Power Rough 16L)
“Though this string lacks touch and feel, it plays quite well at net. There is a high-pitched ping on ground strokes. It is quite stiff, even with a tension reduction. Playability improves over time.” 4.5 male all court player using Head MicroGEL Radical MP strung at 54 pounds LO (Babolat Xcel Premium 16)
“Finally, a polyester that delivers power and control to the non-poly player. I’ve never been a fan of polyester, but this string has piqued my interest.” 4.0 male all court player using Wilson n1 strung at 62 pounds LO (Tecnifibre X One Biphase 17)
“Above average comfort for a polyester. There is definitely a little extra power.” 4.0 male all court player using Prince O3 Hybrid Hornet OS strung at 55 pounds LO (Natural Gut 16)
“The ball comes off the string bed with nice pop. Tension loss and string movement are minimal. Control is excellent.” 4.0 male baseliner with moderate spin using Babolat Pure Storm Tour GT strung at 36 pounds CP (Tourna Big Hitter Blue 17)
“The feel is soft, especially in warm weather. Bite is exceptional. Power is higher than expected, given the breed.” 4.0 male baseliner with heavy spin using Dunlop 200g (Muscle Weave) strung at 60 pounds CP (Prince Synthetic Gut w/Duraflex 16)
“This is a comfortable polyester with excellent control and spin. There is plenty of feel for touch shots.” 5.0 male baseliner with heavy spin using Babolat Aero Storm Tour strung at 55/52 pounds CP (Natural Gut/Babolat Pro Hurricane Tour 16/16)
“It takes an hour of hitting before the feel and playability improve. Durability, tension maintenance, and control are excellent. Power is on the low side. Very easy on the shoulder.” 4.5 male all court player using Babolat AeroPro Drive strung at 51 pounds LO (Babolat VS Team/Genesis Typhoon 17/17)
“This is a stiff string with pop. The shape adds bite.” 5.0 male all court player using Wilson BLX Tour strung at 52 pounds CP (Wilson Sensation 16)
“This string plays better than it handles. It is one of the best control strings I’ve used. The lack of power means you can swing hard and keep the ball inside the lines. Off center hits are a bit harsh. Hard hitters, string breakers, and young guns will like this string.” 4.5 male all court player using Pro Kennex Kinetic Pro 7g strung at 63 pounds CP (Prince Lightning XX 16)
“This string is firm without being harsh. Power and spin are average. String movement is nonexistent, which perhaps explains why I can sense the ball turning into a pancake on the string bed. Any way you slice it, control is amazing.” 4.5 male all court player using Wilson K Pro Staff strung at 58 pounds LO (Luxilon Alu Power 16L)
“While I’m not a polyester player, I cannot argue with the feel and comfort of this string.” 5.0 male serve-and-volley player using Prince O3 Hybrid Comp MP strung at 58 pounds LO (Prince Premier LT 16)
“This comfortable poly grabs the ball. Durability is lacking.” 5.0 male all court player using Head Youtek Radical Pro strung at 55 pounds CP (Tecnifibre Black Code 17)
“After several hours of play, there are no signs of wear. The feel is too stiff for touch shots. This is recommended to big hitters in search of durability. Finesse players are strongly advised to lower the tension or hybrid this with a soft partner.” 5.5 male serve-and-volley player using Wilson BLX Blade Team strung at 58 pounds CP (Prince Beast XP 16)
“While tension maintenance is decent, this string does not provide sufficient power or comfort.” 5.0 male all court player using Babolat Pure Drive Cortex strung at 59 pounds CP (Tecnifibre Black Code 16)
“This is a stiff string. Big swings find the court. It definitely exacts a price from the tendons.” 5.5 male all court player using Babolat Pure Drive strung at 55 pounds CP (Babolat VS Team 17)
“This poly has a surprisingly good feel. It should reach a wide cross-section of players and styles.” 5.0 male all court player using Prince EXO3 White strung at 58 pounds CP (Prince Premier LT 16)
“This is a decent string, but it goes dead quickly. It feels great in the beginning, but over time more work is required to achieve depth.” 4.0 male serve-and-volley player using Wilson Pro Staff 6.1 Stretch strung at 51 pounds LO (Babolat VS Team/Gamma TNT2 Fat Core 17/16)
“This string is a little under powered. Feel on volleys is exceptional. Bite is also impressive.” 4.0 male all court player using Babolat AeroPro Drive Cortex strung at 62 pounds CP (Gamma TNT2 16)
“As a nylon user, I am surprised by this string’s high level of touch and feel. Even so, I think a tension reduction is necessary for those with compact strokes.” 4.5 male all court player using Prince O3 Red MP strung at 52 pounds CP (Prince Synthetic Gut w/Duraflex 17)
“This is a decent co-poly. It plays much softer than it handles. After a few hours, however, tension and feel go south.” 6.0 male all court player using Vantage VT002 White strung at 60 pounds CP (Natural Gut 16)
“This string loses tension very rapidly and becomes too springy.” 4.5 male all court player using Wilson nTour strung at 58 pounds LO (Wilson NXT 17)
“This is an unforgiving string that is too stiff on touch shots. It is recommended to big hitters.” 4.0 female all court player using Prince O3 Tour MS strung at 52 pounds CP (Tecnifibre NRG2 17)
“This poly requires extra effort to achieve depth and control. Those with sensitive tendons might want to install this with a soft cross.” 4.0 male all court player using Volkl Power Bridge 10 Mid strung at 50 pounds CP (Tourna Big Hitter Rough 17)
“This is a stiff polyester. Control is decent, but comfort and touch are lacking. Low tensions are advised.” 4.0 male baseliner with moderate spin using Head MicroGEL Prestige Mid strung at 43 pounds CP (Signum Pro Poly Plasma 16)
“This string is too stiff to be used as a full poly set up.” 3.5 male touch player using Wilson nRage strung at 52 pounds CP (Prince Synthetic Gut w/Duraflex 17)
(Strings normally used by testers are indicated in parentheses.)
|EASE OF STRINGING
(compared to other strings)
|Number of testers who said it was:|
|about as easy||16|
|not quite as easy||21|
|not nearly as easy||4|
(compared to string played most often)
|Number of testers who said it was:|
|about as playable||7|
|not quite as playable||25|
|not nearly as playable||3|
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||11|
|not quite as durable||1|
|not nearly as durable||1|
|From 1 to 5 (best)|
|Durability (11th overall)||4.4|
|Power (20th overall)||3.6|
|Control (5th overall)||3.9|
|Spin Potential (5th overall)||3.9|
|Resistance to Movement (18th overall)||4.0|
See all articles by Greg Raven
About the Author
Greg Raven is an associate editor for RSI magazine and technical writer. He is certified as a Master Racquet Technician by the U.S. Racquet Stringers Association. He can be reached via e-mail at firstname.lastname@example.org, or through Facebook, LinkedIn, and Twitter. He plays tennis five days a week, and is turning into an avid cyclist.